Multiple objects with equal spacing on Follow Path constraint?
Instead of a follow path constraint, use a Ctrl + P > Follow Path type of parent on your object.

Adjust framing as necessary, then go to the 3D View Menu > Object > Animation > Bake Action. Tick to activate all the options.

Then with your object selected go to the Properties Window > Object Tab > Duplication > Frames



Also see Is there a way to convert a constraint to a keyframe?